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WO2014115296A1 - Heat treatment method for metal member and heat-treated metal member - Google Patents

Heat treatment method for metal member and heat-treated metal member Download PDF

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Publication number
WO2014115296A1
WO2014115296A1 PCT/JP2013/051570 JP2013051570W WO2014115296A1 WO 2014115296 A1 WO2014115296 A1 WO 2014115296A1 JP 2013051570 W JP2013051570 W JP 2013051570W WO 2014115296 A1 WO2014115296 A1 WO 2014115296A1
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WO
WIPO (PCT)
Prior art keywords
cooling
heat
workpiece
metal member
processing
Prior art date
Application number
PCT/JP2013/051570
Other languages
French (fr)
Japanese (ja)
Inventor
功二 稲垣
金澤 孝明
Original Assignee
トヨタ自動車株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by トヨタ自動車株式会社 filed Critical トヨタ自動車株式会社
Priority to PCT/JP2013/051570 priority Critical patent/WO2014115296A1/en
Priority to CN201380071332.2A priority patent/CN104937117B/en
Priority to US14/763,365 priority patent/US20150361516A1/en
Priority to JP2014558379A priority patent/JPWO2014115296A1/en
Publication of WO2014115296A1 publication Critical patent/WO2014115296A1/en

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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18Hardening; Quenching with or without subsequent tempering
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H55/00Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/32Friction members
    • F16H55/52Pulleys or friction discs of adjustable construction
    • F16H55/56Pulleys or friction discs of adjustable construction of which the bearing parts are relatively axially adjustable
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24CABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/08Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62Quenching devices
    • C21D1/667Quenching devices for spray quenching
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D11/00Process control or regulation for heat treatments
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00Heat treatment of ferrous alloys
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00Modifying the physical properties of iron or steel by deformation
    • C21D7/02Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • C21D7/08Modifying the physical properties of iron or steel by deformation by cold working of the surface by burnishing or the like
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/32Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H55/00Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/32Friction members
    • F16H55/36Pulleys
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2261/00Machining or cutting being involved
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00Modifying the physical properties of iron or steel by deformation
    • C21D7/02Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • C21D7/06Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H55/00Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/32Friction members
    • F16H2055/325Friction members characterized by roughness or hardness of friction surface

Definitions

  • the present invention relates to a heat treatment method for a metal member that is quenched or quenched by mist cooling that cools a metal workpiece with sprayed cooling water, and a metal member that has been heat treated using the heat treatment method. is there.
  • mist cooling for cooling the workpiece with cooling water sprayed in the form of mist has been performed.
  • mist cooling since the work is cooled by utilizing the action of sensible heat and latent heat when the sprayed cooling water collides with the work, a higher cooling effect can be obtained as compared with the conventional cooling method.
  • the invention described in Japanese Patent Application Laid-Open No. 2011-12221 relates to a mist cooling method in which a cooling mist is injected onto a heated metal workpiece to cool the workpiece.
  • the first nozzle for injecting the cooling mist and the cooling mist having a particle diameter smaller than the particle diameter of the cooling mist injected from the first nozzle.
  • Two types of nozzles, the second nozzle for injecting the liquid are used to cool the workpiece.
  • the heat-treated workpiece can be cooled at a wide range of cooling rates. For example, rapid cooling is performed in a certain period and other periods are performed. However, it is said that uniform and gentle cooling can be performed in order to prevent the occurrence of distortion and bending.
  • the cooling rate can be controlled by adjusting the injection amount and the injection time of the cooling water. Further, as in the invention described in the above Japanese Patent Application Laid-Open No. 2011-12211, by using different types of nozzles having different nozzle diameters, or by adjusting the number, position, injection angle, or injection pressure of the nozzles. The cooling rate can be controlled to perform appropriate cooling according to the size and shape of the workpiece.
  • the sizes and shapes of the workpieces that are actually manufactured are various, and it has been difficult to perform uniform and appropriate cooling by mist cooling corresponding to such various workpieces.
  • mist cooling a workpiece having a shape and a calorie distribution as shown in FIG. 9, as shown in FIG.
  • uniform and appropriate cooling can be performed corresponding to the heat distribution of the workpiece.
  • each time the shape or type of the workpiece is changed it is necessary to adjust the nozzles corresponding to the new workpiece, and it is difficult to perform mist cooling appropriately for all the various workpieces.
  • the present invention has been made by paying attention to the above technical problems, and can easily control the cooling rate corresponding to various workpieces, and can be baked by mist cooling that can perform uniform and appropriate cooling. It is an object of the present invention to provide a heat treatment method for a metal member that is subjected to insertion or rapid cooling, and a metal member that has been heat treated using the heat treatment method.
  • the present invention provides a heating process for heating a metal workpiece under a predetermined heating condition, and a mist cooling that performs cooling by spraying cooling water after the heating process.
  • the heat treatment method for a metal member having a cooling step of cooling the workpiece under the cooling conditions of the workpiece the workpiece according to the heat distribution of the workpiece when heated in the heating step before the heating step It has the surface processing process of adjusting and processing the surface roughness of this, It is the heat processing method of the metal members characterized by the above-mentioned.
  • the surface processing step in the present invention includes a step of processing the workpiece so that the surface roughness becomes smaller as the heat amount of the heat distribution becomes larger.
  • the cooling step in the present invention includes a step of spraying the cooling water so that an average particle diameter of spray droplets in the mist cooling is in a range of 0.1 mm to 2.0 mm.
  • the workpiece in the present invention includes steel automobile parts.
  • the workpiece according to the present invention includes constituent members constituting a pulley of a belt type continuously variable transmission.
  • the surface processing step in the present invention includes a step of processing the workpiece by machining.
  • the surface processing step in the present invention includes a step of processing the workpiece by at least one of shot peening, shot blasting, sand blasting, grinding, or polishing.
  • the present invention relates to a metal member that has been heated under a predetermined heating condition and then subjected to a heat treatment for cooling under a predetermined cooling condition by mist cooling in which cooling water is sprayed for cooling.
  • a heat-treated metal member characterized in that the surface roughness is adjusted according to the heat distribution when heated under conditions, and the heat treatment is performed after the processing. .
  • the metal member according to the present invention may be configured such that the surface roughness is reduced so that the surface roughness becomes smaller as the heat amount of the heat distribution increases.
  • the metal member in the present invention includes steel automobile parts.
  • the said metal member in this invention contains the steel member which comprises the pulley of a belt-type continuously variable transmission.
  • the surface of the metal workpiece is heated in the surface roughness adjustment step before the predetermined heat treatment is performed in the heating step and the cooling step by mist cooling.
  • the surface roughness is adjusted in accordance with the amount of heat in the heat amount distribution when heated at.
  • the processing target surface roughness is set to a smaller value in the portion where the heat quantity distribution at the time of heating in the heating process is larger.
  • the cooling rate when the work is subjected to mist cooling can be controlled by adjusting the surface roughness of the work to be heat-treated. For example, at locations where the amount of heat in the heat distribution when the workpiece is heated is high, the cooling rate during mist cooling is increased by processing the surface of the workpiece so that the surface roughness is reduced in the previous process of heat treatment. can do. On the other hand, in the part where the heat quantity of the heat quantity distribution is small, the cooling rate at the time of mist cooling can be slowed by processing the surface of the workpiece so that the surface roughness becomes large in the pre-process of heat treatment.
  • the cooling rate during the subsequent mist cooling can be controlled. That is, the cooling rate of the workpiece can be controlled without adjusting the position and quantity of nozzles for mist cooling or the cooling water injection state on the cooling equipment side.
  • the cooling rate of the workpiece can be controlled without adjusting the position and quantity of nozzles for mist cooling or the cooling water injection state on the cooling equipment side.
  • transformation by heat processing can be manufactured by implementing appropriate heat processing as mentioned above. As a result, the finishing process after the heat treatment can be omitted or simplified, and the manufacturing cost of the metal member can be greatly reduced.
  • the workpiece surface in the surface machining process can be easily adjusted by adjusting the surface roughness of the workpiece, for example, by machining such as lathe machining or milling.
  • the surface roughness of the workpiece can be easily adjusted and processed by shot peening, shot blasting, sand blasting, grinding, polishing, or the like.
  • the surface of the metal member is processed with the surface roughness adjusted according to the heat distribution when heated during the heat treatment.
  • the heat processing is implemented after the process.
  • the cooling rate increases as the surface roughness of the workpiece decreases as shown in FIG.
  • a portion having a large calorific value in a calorie distribution when a metal member is heated is processed so that the surface roughness is small, whereby the cooling rate at the time of mist cooling can be increased.
  • the cooling rate at the time of mist cooling can be slowed by processing the portion where the heat amount of the heat distribution is small so that the surface roughness is increased.
  • the surface roughness of each part of the metal member is adjusted and processed according to the heat distribution when the heat treatment is performed.
  • the cooling rate at the time of mist cooling in the heat treatment can be controlled. That is, the metal member can be easily and uniformly cooled by mist cooling without adjusting the position and quantity of the nozzles for mist cooling or the cooling water injection state such as the injection state of the cooling water. And by performing appropriate heat processing as mentioned above, the metal member with few distortion and deformation
  • FIG. 6 The result of comparing the amount of deformation of the workpiece when the workpiece is mist cooled by applying the heat treatment method according to the present invention and the amount of deformation of the workpiece when the workpiece is mist cooled without applying the heat treatment method according to the present invention It is a graph for demonstrating.
  • FIG. 1 An example of a metal member targeted by the present invention is shown in FIG.
  • a workpiece 1 shown in FIG. 1 is a metal member in the present invention.
  • the work 1 is a steel automobile part, specifically, a steel member that constitutes a pulley of a belt type continuously variable transmission mounted on the automobile.
  • the workpiece 1 shown in FIG. 1 is a member constituting a fixed sheave in the pulley of the belt type continuously variable transmission.
  • the workpiece 1 is composed of a fixed sheave portion 2 and a shaft portion 3 that is formed integrally with the fixed sheave portion 2 and serves as a pulley shaft.
  • the fixed sheave portion 2 is formed with a sheave surface 2a that forms a winding groove of a transmission belt (not shown) facing the sheave surface of a disk-shaped movable sheave (not shown). Therefore, a pulley of a belt-type continuously variable transmission is configured by inserting a movable sheave movably in the axial direction with respect to the shaft portion 3 of the work 1 and facing the fixed sheave portion 3. .
  • the workpiece 1 is formed into a shape as shown in FIG. 1 by, for example, forging, machining such as lathe processing and counterboring.
  • machining such as lathe processing and counterboring.
  • the outer peripheral surface of the work 1 is formed into a desired shape and size by lathe processing.
  • the axial center part of the axial part 3 is counterbored.
  • the workpiece 1 is subjected to heat treatment for cooling under a predetermined cooling condition after being heated under a predetermined heating condition such as carburizing, nitriding, or carbonitriding. And in this invention, when cooling the heated workpiece
  • the metal member in this invention can make into object all the metal members in which the heat processing cooled by mist cooling is implemented.
  • the steel member as shown in FIG. 1 for example, cast iron, aluminum alloy, or other non-ferrous metal members can be targeted.
  • the workpiece 1 is processed by adjusting the surface roughness of each part of the work 1 in order to control the cooling rate of each part of the work 1 and uniformly cool the whole part of the work 1 during the mist cooling in the heat treatment.
  • the surface roughness of each part of the work 1 is set according to the amount of heat of the heat amount distribution when heated in the heat treatment. That is, the surface of the workpiece 1 is processed so that the surface roughness becomes smaller as the heat quantity of the heat quantity distribution when heated in the heat treatment becomes larger.
  • Such surface processing of the workpiece 1 is performed before the heat treatment for the workpiece 1. Then, as described above, the outer peripheral surface of the work 1 is machined by, for example, lathe processing so as to have a surface roughness set according to the heat distribution of each part of the work 1.
  • the surface of the workpiece 1 has a flat portion, it can be processed to have a desired surface roughness by, for example, milling.
  • other surface processing methods such as shot peening processing, shot blasting processing, sand blasting processing, grinding processing, and polishing processing are also used as described above. It can also be processed to have a desired surface roughness.
  • the work 1 shown in FIG. 1 has a heat distribution when heated in the heat treatment as shown in FIG. That is, when the workpiece 1 is heated in the heat treatment, the intermediate portion 3b of the thick shaft portion 3 and the fixed sheave portion 2 connected to the fixed sheave portion 2 and the shaft portion 3 are formed.
  • the amount of heat in the heat amount distribution is relatively large at the connecting portion 2c, the connecting portion 3c of the shaft portion 3, and the like.
  • the amount of heat in the heat amount distribution becomes relatively small at the outer peripheral end 2b of the fixed sheave portion 2 which is thin, the tip 3a of the shaft portion 3, and the like.
  • This heat quantity distribution can be obtained by actually measuring the temperature of each part of the work 1 when the work 1 is actually heated. Alternatively, it can be estimated and obtained by simulation using a computer.
  • work 1 is each set according to the calorie
  • the intermediate portion 3b having a large heat quantity in the heat quantity distribution is processed with an arithmetic average roughness Ra of 0.8 ⁇ m as a target value.
  • the connecting portion 3c is processed with an arithmetic average roughness Ra of 1.6 ⁇ m as a target value.
  • the connection part 2c is processed by 2.0 micrometers as a target value by arithmetic mean roughness Ra.
  • the tip 3a having a small heat quantity in the heat quantity distribution is processed with an arithmetic average roughness Ra of 3.2 ⁇ m as a target value.
  • the outer peripheral end 2b is processed with an arithmetic average roughness Ra of 6.3 ⁇ m as a target value.
  • the surface roughness of each part of the workpiece 1 is adjusted according to the heat distribution when the workpiece 1 is heated in the heat treatment,
  • the surface of the workpiece 1 is processed. That is, the surface of the workpiece 1 is processed so that the surface roughness becomes smaller as the amount of heat in the heat distribution when the workpiece 1 is heated is larger.
  • the cooling rate increases as the surface roughness of the metal member is smaller. It has been found that more heat is cooled within a predetermined cooling time. The graph of FIG.
  • FIG. 11 shows the measurement result of the cooling time when a test piece whose surface roughness is adjusted using chrome steel as a material is cooled by mist cooling.
  • mist cooling when the cooling water is sprayed so that the average particle diameter of the spray droplets of the cooling water is within the range of 0.1 mm to 2.0 mm, as shown in FIG. It has been found that a sufficient cooling time measurement result can be obtained.
  • the workpiece 1 when the workpiece 1 is mist-cooled in the heat treatment, the workpiece 1 is adjusted so that the cooling rate becomes faster as the heat distribution of the workpiece 1 is larger. Therefore, when the workpiece 1 is mist-cooled for quenching or rapid cooling in heat treatment, the entire workpiece 1 is cooled substantially uniformly. As a result, this workpiece 1 can be subjected to good heat treatment with less distortion and deformation.
  • the heat treatment method in the present invention is, for example, a heat treatment method for carburizing a steel workpiece 1. And in the heat processing method in this invention, mist cooling is implemented in the hardening (cooling) process after a heating process. Furthermore, in the heat treatment method according to the present invention, in addition to the heating step and the quenching step, the heat distribution when the workpiece 1 is heated in the heating step before the heat treatment performed in the heating step and the quenching step. The surface roughness process of adjusting the surface roughness of the workpiece 1 according to the above and machining the surface of the workpiece 1 is provided. Specifically, as shown in FIG.
  • the heat treatment method according to the present invention comprises a forming step (process P0), a surface processing step (process P1), a heating step (process P2), and a cooling (quenching) step in the order of steps. (Process P3) and the finishing process (Process P4).
  • the material steel is forged to form the workpiece 1 material.
  • rough processing by deburring, lathe processing or the like generated by forging is performed. It should be noted that these deburring and roughing processes can be performed collectively in the next surface processing step.
  • the surface roughness of the workpiece 1 is adjusted and processed according to the heat distribution when the workpiece 1 is heated in the next heating step.
  • the heat distribution when the workpiece 1 is heated is obtained in advance by actual measurement, simulation using a computer, or the like.
  • the surface roughness of each part of the workpiece 1 is set as a processing target when the surface of the workpiece 1 is processed.
  • work 1 is processed so that the set surface roughness may be implement
  • the lathe machining or the like of the work 1 is performed so that the surface roughness becomes smaller as the heat amount of the heat distribution when the work 1 is heated is larger. The surface is processed.
  • the cooling rate increases as the surface roughness of the workpiece 1 decreases. This is considered to be influenced by the Leidenfrost phenomenon.
  • Leidenfrost phenomenon when a liquid droplet touches a high-temperature solid surface heated to a temperature higher than the boiling point of the liquid, a vapor layer is formed between the solid surface and the droplet, which inhibits the evaporation of the droplet. It is a phenomenon.
  • the portion where the heat amount of the heat amount distribution when the workpiece 1 is heated is processed so that the surface roughness becomes small, so that the cooling at the time of mist cooling is performed.
  • Speed can be increased.
  • the cooling rate at the time of mist cooling can be slowed by processing the portion where the heat amount of the heat distribution is small so that the surface roughness is increased.
  • the workpiece 1 is heated under a predetermined heating condition and a predetermined gas atmosphere for carburizing, and the state is maintained for a predetermined processing time.
  • a predetermined heating condition and a predetermined gas atmosphere for carburizing for carburizing, and the state is maintained for a predetermined processing time.
  • the workpiece 1 is heated to a carburizing temperature of about 900 to 950 ° C. in a carburizing gas atmosphere in which propane gas or methane gas is modified.
  • the workpiece 1 carburized in the steam heating step is quenched.
  • gas cooling is widely performed for quenching after carburizing, but in the heat treatment method according to the present invention, mist cooling is performed.
  • mist cooling has a higher cooling effect than gas cooling, but it is difficult to adjust cooling equipment in order to set appropriate cooling conditions for all kinds of workpieces. there were. Therefore, in the present invention, the surface processing step is provided as described above before the heat treatment in which the mist cooling is performed. By adjusting the surface roughness of each part of the work 1 in the surface processing step, the cooling rate of each part of the work 1 at the time of subsequent mist cooling can be controlled, and the whole work 1 can be uniformly cooled by mist cooling. I am doing so.
  • the cooling rate of each part of the work 1 in the cooling process can be controlled by adjusting the surface roughness of the work 1 itself without adjusting on the cooling equipment side. . Therefore, in the conventional method, as shown in FIG. 10 described above, adjustment on the cooling equipment side is necessary to control the cooling rate of the workpiece, whereas in the heat treatment method according to the present invention, the cooling equipment is used.
  • the injection nozzles may remain in a simple arrangement as shown in FIG. 3, for example. Further, the injection amount and the injection pressure of the cooling water may be set to be constant.
  • FIG. 4 shows the measurement results of the cooling time of each part of the work 1 when the mist cooling is performed by adjusting the surface roughness of the work 1 as described above to control the cooling rate.
  • FIG. 5 shows the measurement results of the cooling time of each part of the work 1 when mist cooling is performed without controlling the cooling rate.
  • the temperature measurement point a the outer peripheral end portion of the fixed sheave portion 2
  • the cooling rate is relatively fast at b (intermediate portion of the fixed sheave portion 2), whereas the cooling rate is slow at the temperature measurement point c (inner peripheral end portion of the fixed sheave portion 2). Therefore, in this case, it can be seen that the cooling rate of each part of the work 1 during mist cooling varies greatly.
  • the temperature measurement point a when the surface roughness of the workpiece 1 is adjusted by the heat treatment method of the present invention and the cooling rate is controlled and mist cooling is performed, the temperature measurement point a, the temperature measurement point There is no significant difference between b and the temperature measurement point c (the inner peripheral end portion of the fixed sheave portion 2). That is, as shown in FIG. 6, the surface roughness of the workpiece 1 is adjusted without adjusting the surface roughness of the workpiece 1 and compared with the variation in the cooling rate when the mist cooling is performed without controlling the cooling rate. And it turns out that the dispersion
  • the heat treatment method according to the present invention by adjusting the surface roughness of the workpiece 1 to control the cooling rate at the time of mist cooling, the variation in the cooling rate among the parts of the workpiece 1 is small.
  • the whole can be cooled uniformly.
  • work 1 can be cooled uniformly at the time of mist cooling, ie, the quenching in heat processing, as shown in FIG. 7, generation
  • the finishing process of the workpiece 1 after carburizing and quenching is performed as described above. For example, removal of the scale generated in the previous process and machining for ensuring the finished dimensions are performed.
  • the entire work 1 can be uniformly cooled during the mist cooling in the heat treatment, and the work 1 with less distortion and deformation due to the heat treatment can be manufactured.
  • the finishing process in this finishing process can also be skipped. Or the machining allowance at the time of finishing is reduced compared with the conventional case, and the cost required for finishing can be reduced accordingly.
  • FIG. 8 As described above, the effect of cost reduction when the workpiece 1 is manufactured by applying the heat treatment method of the present invention is shown in FIG. As shown in FIG. 8, when the quenching is performed by mist cooling to which the heat treatment method of the present invention is applied, the workpiece 1 is manufactured by the conventional method in which quenching is performed by gas cooling. The manufacturing cost can be greatly reduced.
  • the work 1 is subjected to mist cooling.
  • the cooling rate can be controlled. That is, in the portion where the heat quantity of the heat distribution when the work 1 is heated for the heat treatment is large, the surface of the work 1 is processed so that the surface roughness becomes small in the previous process of the heat treatment. The cooling rate can be increased. On the other hand, in the portion where the heat quantity of the heat distribution is small, the cooling rate at the time of mist cooling can be slowed by processing the surface of the workpiece 1 so that the surface roughness is increased in the previous process of heat treatment. .
  • the cooling rate of the workpiece 1 can be controlled without adjusting on the cooling facility side such as the position and quantity of nozzles for mist cooling or the injection state of cooling water.
  • the cooling facility side such as the position and quantity of nozzles for mist cooling or the injection state of cooling water.
  • uniform and appropriate cooling can be easily performed by mist cooling without adjusting or changing the cooling equipment.
  • work 1 is cooled uniformly by mist cooling, and the workpiece
  • the finishing process after the heat treatment can be omitted or simplified, and the manufacturing cost of the workpiece 1, that is, the metal member in the present invention can be greatly reduced.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

A heat treatment method for a metal member, the method comprising a heating process (Process P2) for heating a metal workpiece under specified heating conditions and a cooling process (Process P3) after the heating process for cooling the workpiece under specified cooling conditions by mist-cooling, which accomplishes cooling by spraying cooling water. Prior to the heating process, the method comprises a surface-finishing process (Process P1) for finishing the workpiece by adjusting the surface roughness according to the heat distribution in the workpiece when heated in the heating process.

Description

金属製部材の熱処理方法および熱処理された金属製部材Heat treatment method for metal member and heat treated metal member
 この発明は、噴霧させた冷却水によって金属製のワークを冷却するミスト冷却により焼き入れもしくは急冷を行う金属製部材の熱処理方法、および、その熱処理方法を用いて熱処理された金属製部材に関するものである。 The present invention relates to a heat treatment method for a metal member that is quenched or quenched by mist cooling that cools a metal workpiece with sprayed cooling water, and a metal member that has been heat treated using the heat treatment method. is there.
 近年、金属製のワークを熱処理する際の冷却工程において、霧状に噴射した冷却水によってワークを冷却するミスト冷却が実施されている。このミスト冷却では、噴霧された冷却水がワークに衝突する際の顕熱および潜熱の作用を利用してワークを冷却するため、従来の冷却方式と比較して高い冷却効果を得ることができる。 In recent years, in a cooling process when heat-treating a metal workpiece, mist cooling for cooling the workpiece with cooling water sprayed in the form of mist has been performed. In this mist cooling, since the work is cooled by utilizing the action of sensible heat and latent heat when the sprayed cooling water collides with the work, a higher cooling effect can be obtained as compared with the conventional cooling method.
 上記のような金属の熱処理におけるミスト冷却に関連する発明の一例が、特開2011-122211号公報に記載されている。この特開2011-122211号公報に記載されている発明は、加熱された金属製のワークに冷却用ミストを噴射して冷却するミスト冷却方法に関するものである。この特開2011-122211号公報に記載されている発明では、冷却用ミストを噴射する第1ノズルと、その第1ノズルから噴射される冷却用ミストの粒径よりも小さい粒径の冷却用ミストを噴射する第2ノズルとの2種類のノズルが用いられて、ワークが冷却される。 An example of the invention related to mist cooling in the heat treatment of metals as described above is described in Japanese Patent Application Laid-Open No. 2011-12221. The invention described in Japanese Patent Application Laid-Open No. 2011-12221 relates to a mist cooling method in which a cooling mist is injected onto a heated metal workpiece to cool the workpiece. In the invention described in Japanese Patent Application Laid-Open No. 2011-12211, the first nozzle for injecting the cooling mist, and the cooling mist having a particle diameter smaller than the particle diameter of the cooling mist injected from the first nozzle. Two types of nozzles, the second nozzle for injecting the liquid, are used to cool the workpiece.
 したがって、この特開2011-122211号公報に記載されている発明では、第1ノズルから噴射される冷却用ミストの粒径が第2ノズルから噴射される冷却用ミストの粒径より大きいことから、第1ノズルの冷却用ミスト1粒あたりの気化潜熱量が、第2ノズルの冷却用ミストよりも大きくなる。そのため、この特開2011-122211号公報に記載されている発明によれば、熱処理したワークを広範な冷却速度で冷却することができ、例えば、ある期間では急速な冷却を行うとともに、他の期間では歪みや曲がり等の発生を防止するための均一なかつ緩やかな冷却を行うことができる、とされている。 Therefore, in the invention described in Japanese Patent Application Laid-Open No. 2011-12211, since the particle size of the cooling mist injected from the first nozzle is larger than the particle size of the cooling mist injected from the second nozzle, The amount of latent heat of vaporization per cooling mist of the first nozzle is larger than that of the cooling mist of the second nozzle. Therefore, according to the invention described in Japanese Patent Application Laid-Open No. 2011-122211, the heat-treated workpiece can be cooled at a wide range of cooling rates. For example, rapid cooling is performed in a certain period and other periods are performed. However, it is said that uniform and gentle cooling can be performed in order to prevent the occurrence of distortion and bending.
 このように、ミスト冷却では、良好な冷却効果を得ることができるとともに、冷却水の噴射量や噴射時間を調整することにより、冷却速度を制御することができる。また、上記の特開2011-122211号公報に記載されている発明のようにノズル径が異なる複数種類のノズルを使い分けたり、ノズルの数量や位置あるいは噴射角度や噴射圧力を調整したりすることにより、冷却速度を制御し、ワークの大きさや形状に応じた適切な冷却を行うことができる。 Thus, in mist cooling, a good cooling effect can be obtained, and the cooling rate can be controlled by adjusting the injection amount and the injection time of the cooling water. Further, as in the invention described in the above Japanese Patent Application Laid-Open No. 2011-12211, by using different types of nozzles having different nozzle diameters, or by adjusting the number, position, injection angle, or injection pressure of the nozzles. The cooling rate can be controlled to perform appropriate cooling according to the size and shape of the workpiece.
 その反面、実際に製造するワークの大きさや形状は多種多様であり、そのような多様なワークに対応してミスト冷却によって均一でかつ適切な冷却を行うことは容易ではなかった。例えば、図9に示すような形状および熱量分布を有するワークをミスト冷却する場合は、図10に示すように、ワークに対する各ノズルの位置ならびに噴射角度、および各ノズルの噴射圧力をそれぞれ調整することにより、ワークの熱量分布に対応して均一で適切な冷却を行うことができる。しかしながら、ワークの形状や種類を変更する場合には、その都度、新しいワークに対応してノズルの調整を行わなければならず、多様なワーク全てに対して適切にミスト冷却を実施することは困難であった。 On the other hand, the sizes and shapes of the workpieces that are actually manufactured are various, and it has been difficult to perform uniform and appropriate cooling by mist cooling corresponding to such various workpieces. For example, in the case of mist cooling a workpiece having a shape and a calorie distribution as shown in FIG. 9, as shown in FIG. Thus, uniform and appropriate cooling can be performed corresponding to the heat distribution of the workpiece. However, each time the shape or type of the workpiece is changed, it is necessary to adjust the nozzles corresponding to the new workpiece, and it is difficult to perform mist cooling appropriately for all the various workpieces. Met.
 この発明は上記の技術的課題に着目してなされたものであり、種々のワークに対応して冷却速度を容易に制御することができ、均一で適切な冷却を行うことができるミスト冷却によって焼き入れもしくは急冷を実施する金属製部材の熱処理方法、および、その熱処理方法を用いて熱処理された金属製部材を提供することを目的とするものである。 The present invention has been made by paying attention to the above technical problems, and can easily control the cooling rate corresponding to various workpieces, and can be baked by mist cooling that can perform uniform and appropriate cooling. It is an object of the present invention to provide a heat treatment method for a metal member that is subjected to insertion or rapid cooling, and a metal member that has been heat treated using the heat treatment method.
 上記の目的を達成するために、この発明は、所定の加熱条件の下で金属製のワークを加熱する加熱工程と、前記加熱工程の後に、冷却水を噴霧して冷却を行うミスト冷却によって所定の冷却条件の下で前記ワークを冷却する冷却工程とを有する金属製部材の熱処理方法において、前記加熱工程の前に、前記加熱工程で加熱される際の前記ワークの熱量分布に応じて前記ワークの表面粗さを調整して加工する表面加工工程を有していることを特徴とする金属製部材の熱処理方法である。 In order to achieve the above object, the present invention provides a heating process for heating a metal workpiece under a predetermined heating condition, and a mist cooling that performs cooling by spraying cooling water after the heating process. In the heat treatment method for a metal member having a cooling step of cooling the workpiece under the cooling conditions of the workpiece, the workpiece according to the heat distribution of the workpiece when heated in the heating step before the heating step It has the surface processing process of adjusting and processing the surface roughness of this, It is the heat processing method of the metal members characterized by the above-mentioned.
 また、この発明における前記表面加工工程は、前記熱量分布の熱量が大きい箇所ほど前記表面粗さが小さくなるように前記ワークを加工する工程を含んでいる。 Further, the surface processing step in the present invention includes a step of processing the workpiece so that the surface roughness becomes smaller as the heat amount of the heat distribution becomes larger.
 また、この発明における前記冷却工程は、前記ミスト冷却における噴霧液滴の平均粒径が0.1mmから2.0mmの範囲内となるように前記冷却水を噴霧させる工程を含んでいる。 Further, the cooling step in the present invention includes a step of spraying the cooling water so that an average particle diameter of spray droplets in the mist cooling is in a range of 0.1 mm to 2.0 mm.
 また、この発明における前記ワークは、鋼製の自動車部品を含んでいる。 Further, the workpiece in the present invention includes steel automobile parts.
 また、この発明における前記ワークは、ベルト式無段変速機のプーリを構成する構成部材を含んでいる。 Further, the workpiece according to the present invention includes constituent members constituting a pulley of a belt type continuously variable transmission.
 また、この発明における前記表面加工工程は、機械加工によって前記ワークを加工する工程を含んでいる。 Further, the surface processing step in the present invention includes a step of processing the workpiece by machining.
 そして、この発明における前記表面加工工程は、ショットピーニング加工、ショットブラスト加工、サンドブラスト加工、研削加工、または研磨加工の少なくともいずれかによって前記ワークを加工する工程を含んでいる。 The surface processing step in the present invention includes a step of processing the workpiece by at least one of shot peening, shot blasting, sand blasting, grinding, or polishing.
 一方、この発明は、所定の加熱条件の下で加熱した後に、冷却水を噴霧して冷却を行うミスト冷却によって所定の冷却条件の下で冷却する熱処理が施された金属製部材において、前記加熱条件の下で加熱される際の熱量分布に応じて表面粗さが調整されて加工されているとともに、その加工後に前記熱処理が施されていることを特徴とする熱処理された金属製部材である。 On the other hand, the present invention relates to a metal member that has been heated under a predetermined heating condition and then subjected to a heat treatment for cooling under a predetermined cooling condition by mist cooling in which cooling water is sprayed for cooling. A heat-treated metal member characterized in that the surface roughness is adjusted according to the heat distribution when heated under conditions, and the heat treatment is performed after the processing. .
 また、この発明における前記金属製部材は、前記熱量分布の熱量が大きい箇所ほど前記表面粗さが小さくなるように表面加工された構成とすることができる。 Further, the metal member according to the present invention may be configured such that the surface roughness is reduced so that the surface roughness becomes smaller as the heat amount of the heat distribution increases.
 また、この発明における前記金属製部材は、鋼製の自動車部品を含んでいる。 Further, the metal member in the present invention includes steel automobile parts.
 そして、この発明における前記金属製部材は、ベルト式無段変速機のプーリを構成する鋼製部材を含んでいる。 And the said metal member in this invention contains the steel member which comprises the pulley of a belt-type continuously variable transmission.
 上記のようなこの発明の金属製部材の熱処理方法では、加熱工程およびミスト冷却による冷却工程において所定の熱処理が実施される前に、面粗さ調整工程において金属製のワークの表面が、加熱工程で加熱される際の熱量分布の熱量の大きさに応じて表面粗さが調整されて加工される。例えば、加熱工程で加熱される際の熱量分布が大きい箇所ほど加工目標の表面粗さが小さい値に設定されて加工される。金属製部材の熱処理において、水を噴霧してミスト冷却を行う場合、すなわち、水の沸点以上の温度に加熱した金属製のワークをミスト冷却する場合には、図11に示すように、ワークの表面粗さが小さいほど冷却時間が短くなること、すなわち冷却速度が速くなることが分かっている。 In the heat treatment method for a metal member of the present invention as described above, the surface of the metal workpiece is heated in the surface roughness adjustment step before the predetermined heat treatment is performed in the heating step and the cooling step by mist cooling. The surface roughness is adjusted in accordance with the amount of heat in the heat amount distribution when heated at. For example, the processing target surface roughness is set to a smaller value in the portion where the heat quantity distribution at the time of heating in the heating process is larger. When performing mist cooling by spraying water in the heat treatment of a metal member, that is, when mist cooling a metal workpiece heated to a temperature equal to or higher than the boiling point of water, as shown in FIG. It has been found that the smaller the surface roughness, the shorter the cooling time, that is, the higher the cooling rate.
 したがって、この発明の金属製部材の熱処理方法によれば、熱処理を施すワークの表面粗さを調整することにより、そのワークをミスト冷却する際の冷却速度を制御することができる。例えば、ワークを加熱した場合の熱量分布の熱量が大きい箇所は、熱処理の前工程で表面粗さが小さくなるようにワークの表面を加工しておくことにより、ミスト冷却の際の冷却速度を速くすることができる。反対に、熱量分布の熱量が小さい箇所は、熱処理の前工程で表面粗さが大きくなるようにワークの表面を加工しておくことにより、ミスト冷却の際の冷却速度を遅くすることができる。そのため、熱処理前の表面加工工程において、ワークの表面粗さを熱量分布に応じて調整して加工しておくことにより、その後のミスト冷却の際の冷却速度を制御することができる。すなわち、ミスト冷却のためのノズルの位置や数量あるいは冷却水の噴射状態など冷却設備側で調整することなく、ワークの冷却速度を制御することができる。その結果、ワークの大きさや形状を変更した場合であっても、冷却設備の調整や変更を行うことなく、容易に、ミスト冷却によって均一でかつ適切な冷却を行うことができる。そして、上記のように適切な熱処理が実施されることにより、熱処理による歪みや変形が少ない金属製部材を製造することができる。その結果、熱処理後の仕上げ加工を省略もしくは簡略化することができ、金属製部材の製造コストを大幅に削減することができる。 Therefore, according to the heat treatment method for a metal member of the present invention, the cooling rate when the work is subjected to mist cooling can be controlled by adjusting the surface roughness of the work to be heat-treated. For example, at locations where the amount of heat in the heat distribution when the workpiece is heated is high, the cooling rate during mist cooling is increased by processing the surface of the workpiece so that the surface roughness is reduced in the previous process of heat treatment. can do. On the other hand, in the part where the heat quantity of the heat quantity distribution is small, the cooling rate at the time of mist cooling can be slowed by processing the surface of the workpiece so that the surface roughness becomes large in the pre-process of heat treatment. Therefore, in the surface processing step before the heat treatment, by adjusting the surface roughness of the workpiece according to the heat distribution, the cooling rate during the subsequent mist cooling can be controlled. That is, the cooling rate of the workpiece can be controlled without adjusting the position and quantity of nozzles for mist cooling or the cooling water injection state on the cooling equipment side. As a result, even when the size or shape of the workpiece is changed, uniform and appropriate cooling can be easily performed by mist cooling without adjusting or changing the cooling equipment. And metal member with few distortion and deformation | transformation by heat processing can be manufactured by implementing appropriate heat processing as mentioned above. As a result, the finishing process after the heat treatment can be omitted or simplified, and the manufacturing cost of the metal member can be greatly reduced.
 また、表面加工工程におけるワーク表面の加工は、例えば旋盤加工やフライス加工などの機械加工によって、容易にワークの表面粗さを調整して加工することができる。あるいは、ショットピーニング加工、ショットブラスト加工、サンドブラスト加工、研削加工、そして研磨加工などによっても、容易にワークの表面粗さを調整して加工することができる。 Also, the workpiece surface in the surface machining process can be easily adjusted by adjusting the surface roughness of the workpiece, for example, by machining such as lathe machining or milling. Alternatively, the surface roughness of the workpiece can be easily adjusted and processed by shot peening, shot blasting, sand blasting, grinding, polishing, or the like.
 一方、この発明の熱処理された金属製部材では、金属製部材の表面が、熱処理の際に加熱された場合の熱量分布に応じて、表面粗さが調整されて加工される。そしてその加工後に、熱処理が実施される。前述したように、金属製部材の熱処理において、水を噴霧してミスト冷却を行う場合、図11に示すように、ワークの表面粗さが小さいほど冷却速度が速くなることが分かっている。例えば、金属製部材を加熱した場合の熱量分布の熱量が大きい箇所は、表面粗さが小さくなるように加工しておくことにより、ミスト冷却の際の冷却速度を速くすることができる。反対に、熱量分布の熱量が小さい箇所は、表面粗さが大きくなるように加工しておくことにより、ミスト冷却の際の冷却速度を遅くすることができる。 On the other hand, in the heat-treated metal member of the present invention, the surface of the metal member is processed with the surface roughness adjusted according to the heat distribution when heated during the heat treatment. And the heat processing is implemented after the process. As described above, in the heat treatment of a metal member, when water is sprayed to perform mist cooling, it is known that the cooling rate increases as the surface roughness of the workpiece decreases as shown in FIG. For example, a portion having a large calorific value in a calorie distribution when a metal member is heated is processed so that the surface roughness is small, whereby the cooling rate at the time of mist cooling can be increased. On the contrary, the cooling rate at the time of mist cooling can be slowed by processing the portion where the heat amount of the heat distribution is small so that the surface roughness is increased.
 したがって、この発明の熱処理された金属製部材によれば、上記のように、金属製部材各部の表面粗さが、熱処理を実施した際の熱量分布に応じて調整されて加工されることにより、熱処理におけるミスト冷却の際の冷却速度を制御することができる。すなわち、ミスト冷却のためのノズルの位置や数量あるいは冷却水の噴射状態など冷却設備側で調整を行うことなく、容易に、ミスト冷却によって均一でかつ適切に金属製部材を冷却することができる。そして、上記のように適切な熱処理が実施されることにより、熱処理による歪みや変形の少ない金属製部材を製造することができる。その結果、熱処理後の仕上げ加工を省略もしくは簡略化することができ、製造コストを大幅に削減した金属製部材を提供することができる。 Therefore, according to the heat-treated metal member of the present invention, as described above, the surface roughness of each part of the metal member is adjusted and processed according to the heat distribution when the heat treatment is performed. The cooling rate at the time of mist cooling in the heat treatment can be controlled. That is, the metal member can be easily and uniformly cooled by mist cooling without adjusting the position and quantity of the nozzles for mist cooling or the cooling water injection state such as the injection state of the cooling water. And by performing appropriate heat processing as mentioned above, the metal member with few distortion and deformation | transformation by heat processing can be manufactured. As a result, the finishing process after the heat treatment can be omitted or simplified, and a metal member that can greatly reduce the manufacturing cost can be provided.
この発明で対象とする金属製部材の一例を示す模式図である。It is a schematic diagram which shows an example of the metal members made into object by this invention. この発明に係る熱処理方法によって実施されるワークの表面粗さの調整および熱処理の一例を説明するための工程図である。It is process drawing for demonstrating an example of adjustment of the surface roughness of the workpiece | work implemented by the heat processing method which concerns on this invention, and heat processing. この発明に係る熱処理方法および金属製部材において適用されるミスト冷却のための冷却設備の一例を説明するための模式図である。It is a schematic diagram for demonstrating an example of the cooling equipment for the mist cooling applied in the heat processing method and metal member which concern on this invention. この発明に係る熱処理方法を適用してワークをミスト冷却した場合のワーク各部の冷却速度のばらつきを説明するためのグラフである。It is a graph for demonstrating the dispersion | variation in the cooling rate of each part of a workpiece | work when the workpiece | work is mist-cooled by applying the heat processing method which concerns on this invention. この発明に係る熱処理方法を適用せずにワークをミスト冷却した場合のワーク各部の冷却速度のばらつきを説明するためのグラフである。It is a graph for demonstrating the dispersion | variation in the cooling rate of each part of a workpiece | work at the time of carrying out mist cooling of the workpiece | work, without applying the heat processing method which concerns on this invention. 図4,図5に示す冷却速度のばらつきを比較した結果を説明するためのグラフである。6 is a graph for explaining the result of comparing the cooling rate variations shown in FIGS. 4 and 5. FIG. この発明に係る熱処理方法を適用してワークをミスト冷却した場合のワークの変形量と、この発明に係る熱処理方法を適用せずにワークをミスト冷却した場合のワークの変形量とを比較した結果を説明するためのグラフである。The result of comparing the amount of deformation of the workpiece when the workpiece is mist cooled by applying the heat treatment method according to the present invention and the amount of deformation of the workpiece when the workpiece is mist cooled without applying the heat treatment method according to the present invention It is a graph for demonstrating. この発明に係る熱処理方法を適用して場合のワークの製造コストと、この発明に係る熱処理方法を適用しない場合のワークの製造コストとを比較した結果を説明するためのグラフである。It is a graph for demonstrating the result of having compared the manufacturing cost of the workpiece | work when the heat processing method which concerns on this invention is applied, and the manufacturing cost of the workpiece | work when not applying the heat processing method which concerns on this invention. この発明で対象とする金属製部材の一例であって、その金属製部材を熱処理する際に加熱した場合の熱量分布を示す模式図である。It is an example of the metal member made into object by this invention, Comprising: It is a schematic diagram which shows heat amount distribution at the time of heating when heat-treating the metal member. 従来の方法により、図9に示す金属製部材をミスト冷却する場合の冷却条件設定の一例を示す模式図である。It is a schematic diagram which shows an example of the cooling condition setting in the case of carrying out mist cooling of the metal members shown in FIG. 9 by a conventional method. 金属製部材をミスト冷却した場合の表面粗さと冷却速度との関係を説明するための模式図である。It is a schematic diagram for demonstrating the relationship between the surface roughness at the time of carrying out mist cooling of metal members, and a cooling rate.
 次に、この発明を図面を参照して具体的に説明する。この発明で対象とする金属製部材の一例を図1に示してある。この図1に示すワーク1は、この発明における金属製部材である。この図1に示す例では、ワーク1は、鋼製の自動車部品であり、具体的には、自動車に搭載されるベルト式無段変速機のプーリを構成する鋼製部材である。より具体的には、この図1に示すワーク1は、ベルト式無段変速機のプーリにおける固定シーブを構成する部材である。そのために、ワーク1は、固定シーブ部2と、その固定シーブ部2と一体に形成されてプーリ軸になる軸部3とから構成されている。固定シーブ部2には、円盤形状の可動シーブ(図示せず)のシーブ面と対向して伝動ベルト(図示せず)の巻き掛かり溝を形成するシーブ面2aが形成されている。したがって、ワーク1の軸部3に対して可動シーブを軸線方向で移動可能に挿入して固定シーブ部3と対向させることにより、ベルト式無段変速機のプーリが構成されるようになっている。 Next, the present invention will be specifically described with reference to the drawings. An example of a metal member targeted by the present invention is shown in FIG. A workpiece 1 shown in FIG. 1 is a metal member in the present invention. In the example shown in FIG. 1, the work 1 is a steel automobile part, specifically, a steel member that constitutes a pulley of a belt type continuously variable transmission mounted on the automobile. More specifically, the workpiece 1 shown in FIG. 1 is a member constituting a fixed sheave in the pulley of the belt type continuously variable transmission. For this purpose, the workpiece 1 is composed of a fixed sheave portion 2 and a shaft portion 3 that is formed integrally with the fixed sheave portion 2 and serves as a pulley shaft. The fixed sheave portion 2 is formed with a sheave surface 2a that forms a winding groove of a transmission belt (not shown) facing the sheave surface of a disk-shaped movable sheave (not shown). Therefore, a pulley of a belt-type continuously variable transmission is configured by inserting a movable sheave movably in the axial direction with respect to the shaft portion 3 of the work 1 and facing the fixed sheave portion 3. .
 上記のワーク1は、例えば、鍛造加工、および、旋盤加工ならびにざぐり加工などの機械加工により、図1に示すような形状に成形されている。例えば、鍛造加工により固定シーブ部2と軸部3とが一体に成形された後に、旋盤加工によりワーク1の外周表面が所望する形状・寸法に成形されている。そして、他部材との連結・固定用の部位や潤滑油の油路を形成するために、軸部3の軸心部分がざぐり加工されている。 The workpiece 1 is formed into a shape as shown in FIG. 1 by, for example, forging, machining such as lathe processing and counterboring. For example, after the fixed sheave portion 2 and the shaft portion 3 are integrally formed by forging, the outer peripheral surface of the work 1 is formed into a desired shape and size by lathe processing. And in order to form the site | part for a connection and fixation with another member, and the oil path of lubricating oil, the axial center part of the axial part 3 is counterbored.
 また、ワーク1は、例えば、浸炭、窒化、あるいは浸炭窒化など、所定の加熱条件の下で加熱した後に、所定の冷却条件の下で冷却する熱処理が施されている。そして、この発明では、上記のような熱処理において、焼き入れもしくは急冷など、加熱されたワーク1を冷却する際には、冷却水を噴霧して冷却を行ういわゆるミスト冷却が実施されている。 Also, the workpiece 1 is subjected to heat treatment for cooling under a predetermined cooling condition after being heated under a predetermined heating condition such as carburizing, nitriding, or carbonitriding. And in this invention, when cooling the heated workpiece | work 1 in quenching or rapid cooling in the above heat processing, what is called mist cooling which sprays cooling water and cools is implemented.
 なお、この発明における金属製部材は、ミスト冷却によって冷却される熱処理が実施される全ての金属製の部材を対象とすることができる。この図1に示すような鋼製の部材以外に、例えば、鋳鉄製やアルミニウム合金製あるいはその他の非鉄金属製の部材も対象にすることができる。 In addition, the metal member in this invention can make into object all the metal members in which the heat processing cooled by mist cooling is implemented. In addition to the steel member as shown in FIG. 1, for example, cast iron, aluminum alloy, or other non-ferrous metal members can be targeted.
 そして、ワーク1は、熱処理におけるミスト冷却の際に、ワーク1各部の冷却速度を制御して、ワーク1の全体を均一に冷却させるために、ワーク1各部の表面粗さがそれぞれ調整されて加工されている。具体的には、ワーク1各部の表面粗さが、熱処理において加熱した際の熱量分布の熱量の大きさに応じて設定されている。すなわち、熱処理において加熱した際の熱量分布の熱量が大きい箇所ほど表面粗さが小さくなるように、ワーク1の表面が加工されている。 The workpiece 1 is processed by adjusting the surface roughness of each part of the work 1 in order to control the cooling rate of each part of the work 1 and uniformly cool the whole part of the work 1 during the mist cooling in the heat treatment. Has been. Specifically, the surface roughness of each part of the work 1 is set according to the amount of heat of the heat amount distribution when heated in the heat treatment. That is, the surface of the workpiece 1 is processed so that the surface roughness becomes smaller as the heat quantity of the heat quantity distribution when heated in the heat treatment becomes larger.
 このようなワーク1の表面加工は、ワーク1に対する熱処理の前に実施されている。そして、上記のようにワーク1の外周面がワーク1各部の熱量分布に応じて設定された表面粗さとなるように、例えば旋盤加工により加工されている。ワーク1の表面に平面部分がある場合には、例えばフライス加工によって、所望する表面粗さとなるように加工することもできる。あるいは、上記のような旋盤加工やフライス加工などの機械加工以外に、例えば、ショットピーニング加工、ショットブラスト加工、サンドブラスト加工、研削加工、そして研磨加工などのその他の表面加工方法によっても、上記のように所望する表面粗さとなるように加工することもできる。 Such surface processing of the workpiece 1 is performed before the heat treatment for the workpiece 1. Then, as described above, the outer peripheral surface of the work 1 is machined by, for example, lathe processing so as to have a surface roughness set according to the heat distribution of each part of the work 1. When the surface of the workpiece 1 has a flat portion, it can be processed to have a desired surface roughness by, for example, milling. Alternatively, in addition to machining such as lathe processing and milling as described above, other surface processing methods such as shot peening processing, shot blasting processing, sand blasting processing, grinding processing, and polishing processing are also used as described above. It can also be processed to have a desired surface roughness.
 この図1に示すワーク1は、熱処理において加熱された際の熱量分布が、前述の図9に示したようになっている。すなわち、ワーク1は、熱処理において加熱された際には、厚肉になっている軸部3の中間部3b、および、固定シーブ部2と軸部3との連結している固定シーブ部2の連結部2cならびに軸部3の連結部3cなどで、熱量分布における熱量が相対的に大きくなる。一方、薄肉になっている固定シーブ部2の外周端部2b、および、軸部3の先端部3aなどで、熱量分布における熱量が相対的に小さくなる。この熱量分布は、ワーク1を実際に加熱した際にワーク1各部の温度を実測することにより求めることができる。あるいは、コンピュータを用いたシミュレーションによって推定して求めることもできる。 The work 1 shown in FIG. 1 has a heat distribution when heated in the heat treatment as shown in FIG. That is, when the workpiece 1 is heated in the heat treatment, the intermediate portion 3b of the thick shaft portion 3 and the fixed sheave portion 2 connected to the fixed sheave portion 2 and the shaft portion 3 are formed. The amount of heat in the heat amount distribution is relatively large at the connecting portion 2c, the connecting portion 3c of the shaft portion 3, and the like. On the other hand, the amount of heat in the heat amount distribution becomes relatively small at the outer peripheral end 2b of the fixed sheave portion 2 which is thin, the tip 3a of the shaft portion 3, and the like. This heat quantity distribution can be obtained by actually measuring the temperature of each part of the work 1 when the work 1 is actually heated. Alternatively, it can be estimated and obtained by simulation using a computer.
 そして、この発明におけるワーク1は、上記のように熱処理においてワーク1が加熱された際の熱量分布に応じて、ワーク1各部の表面粗さがそれぞれ設定されている。すなわち、上記のように、熱量分布における熱量が相対的に大きくなる連結部2c、連結部3c、および中間部3bなどの箇所が、相対的に表面粗さが小さくなるように加工されている。そして、熱量分布における熱量が相対的に小さくなる外周端部2b、および先端部3aなどの箇所が、相対的に表面粗さが大きくなるように加工されている。具体的には、図1に示すように、熱量分布における熱量が大きい中間部3bが、算術平均粗さRaで0.8μmを目標値として加工されている。また、連結部3cが、算術平均粗さRaで1.6μmを目標値として加工されている。そして、連結部2cが、算術平均粗さRaで2.0μmを目標値として加工されている。一方、熱量分布における熱量が小さい先端部3aが、算術平均粗さRaで3.2μmを目標値として加工されている。そして、外周端部2bが、算術平均粗さRaで6.3μmを目標値として加工されている。 And as for the workpiece | work 1 in this invention, the surface roughness of each part of the workpiece | work 1 is each set according to the calorie | heat amount distribution when the workpiece | work 1 is heated in heat processing as mentioned above. That is, as described above, portions such as the connecting portion 2c, the connecting portion 3c, and the intermediate portion 3b where the amount of heat in the heat distribution is relatively large are processed so that the surface roughness is relatively small. And locations such as the outer peripheral end 2b and the front end 3a where the heat quantity in the heat quantity distribution is relatively small are processed so that the surface roughness is relatively large. Specifically, as shown in FIG. 1, the intermediate portion 3b having a large heat quantity in the heat quantity distribution is processed with an arithmetic average roughness Ra of 0.8 μm as a target value. The connecting portion 3c is processed with an arithmetic average roughness Ra of 1.6 μm as a target value. And the connection part 2c is processed by 2.0 micrometers as a target value by arithmetic mean roughness Ra. On the other hand, the tip 3a having a small heat quantity in the heat quantity distribution is processed with an arithmetic average roughness Ra of 3.2 μm as a target value. The outer peripheral end 2b is processed with an arithmetic average roughness Ra of 6.3 μm as a target value.
 このように、ワーク1すなわちこの発明における金属製部材は、熱処理が実施される前に、熱処理においてワーク1が加熱される際の熱量分布に応じてワーク1各部の表面粗さが調整されて、そのワーク1の表面が加工されている。すなわち、ワーク1が加熱される際の熱量分布の熱量が大きい箇所ほど表面粗さが小さくなるように、ワーク1の表面が加工されている。前述の図11で示して説明したように、加熱した金属製部材に対して水を噴霧してミスト冷却を行う場合は、金属製部材の表面粗さが小さい箇所ほど冷却速度が速くなる、すなわち所定の冷却時間内により多くの熱量が冷却されることが分かっている。なお、この図11のグラフは、クロム鋼を材料として表面粗さを調整したテストピースを、ミスト冷却によって冷却した場合の冷却時間の測定結果を示している。そして、この場合のミスト冷却においては、冷却水の噴霧液滴の平均粒径が0.1mmから2.0mmの範囲内となるように冷却水を噴霧させた場合に、この図11に示すような冷却時間の測定結果が得られることが分かっている。 Thus, before the heat treatment is performed on the workpiece 1, that is, the metal member in the present invention, the surface roughness of each part of the workpiece 1 is adjusted according to the heat distribution when the workpiece 1 is heated in the heat treatment, The surface of the workpiece 1 is processed. That is, the surface of the workpiece 1 is processed so that the surface roughness becomes smaller as the amount of heat in the heat distribution when the workpiece 1 is heated is larger. As shown in FIG. 11 and described above, when water is sprayed on a heated metal member to perform mist cooling, the cooling rate increases as the surface roughness of the metal member is smaller. It has been found that more heat is cooled within a predetermined cooling time. The graph of FIG. 11 shows the measurement result of the cooling time when a test piece whose surface roughness is adjusted using chrome steel as a material is cooled by mist cooling. In the mist cooling in this case, when the cooling water is sprayed so that the average particle diameter of the spray droplets of the cooling water is within the range of 0.1 mm to 2.0 mm, as shown in FIG. It has been found that a sufficient cooling time measurement result can be obtained.
 したがって、このワーク1は、熱処理においてミスト冷却される際に、ワーク1の熱量分布が大きい箇所ほど冷却速度が速くなるように調整されている。そのため、このワーク1は、熱処理における焼き入れもしくは急冷のためにミスト冷却される際には、ワーク1の全体がほぼ均一に冷却される。その結果、このワーク1に対しては歪みや変形が少ない良好な熱処理を実施することができる。 Therefore, when the workpiece 1 is mist-cooled in the heat treatment, the workpiece 1 is adjusted so that the cooling rate becomes faster as the heat distribution of the workpiece 1 is larger. Therefore, when the workpiece 1 is mist-cooled for quenching or rapid cooling in heat treatment, the entire workpiece 1 is cooled substantially uniformly. As a result, this workpiece 1 can be subjected to good heat treatment with less distortion and deformation.
 次に、上記のように構成される金属製部材の熱処理方法について説明する。この発明における熱処理方法は、例えば、鋼製のワーク1を浸炭するための熱処理方法である。そして、この発明における熱処理方法では、加熱工程後の焼き入れ(冷却)工程において、ミスト冷却が実施される。さらに、この発明における熱処理方法では、上記の加熱工程および焼き入れ工程に加えて、それら加熱工程および焼き入れ工程で実施される熱処理の前に、ワーク1が加熱工程で加熱される際の熱量分布に応じてワーク1の表面粗さを調整し、ワーク1の表面を加工する表面加工工程を有している。具体的には、この発明における熱処理方法は、図2に示すように、工程順に、成形工程(プロセスP0)、表面加工工程(プロセスP1)、加熱工程(プロセスP2)、冷却(焼き入れ)工程(プロセスP3)、および、仕上げ加工工程(プロセスP4)の各工程により実施される。 Next, a heat treatment method for the metal member configured as described above will be described. The heat treatment method in the present invention is, for example, a heat treatment method for carburizing a steel workpiece 1. And in the heat processing method in this invention, mist cooling is implemented in the hardening (cooling) process after a heating process. Furthermore, in the heat treatment method according to the present invention, in addition to the heating step and the quenching step, the heat distribution when the workpiece 1 is heated in the heating step before the heat treatment performed in the heating step and the quenching step. The surface roughness process of adjusting the surface roughness of the workpiece 1 according to the above and machining the surface of the workpiece 1 is provided. Specifically, as shown in FIG. 2, the heat treatment method according to the present invention comprises a forming step (process P0), a surface processing step (process P1), a heating step (process P2), and a cooling (quenching) step in the order of steps. (Process P3) and the finishing process (Process P4).
 先ず、成形工程(プロセスP0)で、材料の鋼材が鍛造されてワーク1の素材が成形される。そして、鍛造によって生じたばり取りや旋盤加工等による粗加工が行われる。なお、これらのばり取りや粗加工は、次の表面加工工程において一括して行うこともできる。 First, in the forming step (process P0), the material steel is forged to form the workpiece 1 material. And rough processing by deburring, lathe processing or the like generated by forging is performed. It should be noted that these deburring and roughing processes can be performed collectively in the next surface processing step.
 そして、表面加工工程(プロセスP1)では、次の加熱工程でワーク1が加熱された場合の熱量分布に応じて、ワーク1の表面粗さが調整されて加工される。前述したように、ワーク1が加熱された場合の熱量分布は、予め、実測やコンピュータを用いたシミュレーション等によって求められている。そのワーク1の熱量分布のデータを基に、ワーク1の表面を加工する際の加工目標として、ワーク1各部の表面粗さがそれぞれ設定される。そして、設定された表面粗さを実現するように、ワーク1の表面が加工される。具体的には、前述の図1および図9に示したように、ワーク1が加熱された場合の熱量分布の熱量が大きい箇所ほど表面粗さが小さくなるように、旋盤加工等によってワーク1の表面が加工される。 And in the surface processing step (process P1), the surface roughness of the workpiece 1 is adjusted and processed according to the heat distribution when the workpiece 1 is heated in the next heating step. As described above, the heat distribution when the workpiece 1 is heated is obtained in advance by actual measurement, simulation using a computer, or the like. Based on the heat distribution data of the workpiece 1, the surface roughness of each part of the workpiece 1 is set as a processing target when the surface of the workpiece 1 is processed. And the surface of the workpiece | work 1 is processed so that the set surface roughness may be implement | achieved. Specifically, as shown in FIG. 1 and FIG. 9 described above, the lathe machining or the like of the work 1 is performed so that the surface roughness becomes smaller as the heat amount of the heat distribution when the work 1 is heated is larger. The surface is processed.
 前述したように、金属製部材の熱処理において、水を噴霧してミスト冷却を行う場合、図11に示すように、ワーク1の表面粗さが小さいほど冷却速度が速くなることが分かっている。これは、ライデンフロスト現象の影響を受けているものと考えられる。ライデンフロスト現象は、液体の沸点以上に加熱した高温の固体表面に液体の液滴が接すると、固体表面と液滴との間に蒸気の層が生じ、これにより液滴の蒸発が阻害される現象である。金属の表面を水でミスト冷却する場合、金属表面の表面粗さが小さい方が水に対する濡れ性が低くなり、上記のようなライデンフロスト現象が生じ易くなる。そのため、金属表面で冷却水が直ちには蒸発せずに水滴のまま滞留する時間が長くなり、その結果、金属表面の冷却が促進されるものと考えられる。 As described above, when the mist cooling is performed by spraying water in the heat treatment of the metal member, as shown in FIG. 11, it is known that the cooling rate increases as the surface roughness of the workpiece 1 decreases. This is considered to be influenced by the Leidenfrost phenomenon. In the Leidenfrost phenomenon, when a liquid droplet touches a high-temperature solid surface heated to a temperature higher than the boiling point of the liquid, a vapor layer is formed between the solid surface and the droplet, which inhibits the evaporation of the droplet. It is a phenomenon. When the metal surface is mist-cooled with water, the smaller the surface roughness of the metal surface, the lower the wettability with respect to water, and the above-mentioned Leidenfrost phenomenon tends to occur. Therefore, it is considered that the cooling water does not immediately evaporate on the metal surface but stays in the form of water droplets, and as a result, cooling of the metal surface is promoted.
 したがって、この表面加工工程において、上記のように、ワーク1を加熱した場合の熱量分布の熱量が大きい箇所は、表面粗さが小さくなるように加工しておくことにより、ミスト冷却の際の冷却速度を速くすることができる。反対に、熱量分布の熱量が小さい箇所は、表面粗さが大きくなるように加工しておくことにより、ミスト冷却の際の冷却速度を遅くすることができる。 Therefore, in this surface processing step, as described above, the portion where the heat amount of the heat amount distribution when the workpiece 1 is heated is processed so that the surface roughness becomes small, so that the cooling at the time of mist cooling is performed. Speed can be increased. On the contrary, the cooling rate at the time of mist cooling can be slowed by processing the portion where the heat amount of the heat distribution is small so that the surface roughness is increased.
 加熱工程(プロセスP2)では、ワーク1を浸炭するための所定の加熱条件および所定のガス雰囲気の下で加熱され、その状態が所定の処理時間の間保持される。例えば、プロパンガスやメタンガスなどを変成した浸炭性ガス雰囲気内で、ワーク1が約900~950℃の浸炭温度に加熱される。 In the heating step (process P2), the workpiece 1 is heated under a predetermined heating condition and a predetermined gas atmosphere for carburizing, and the state is maintained for a predetermined processing time. For example, the workpiece 1 is heated to a carburizing temperature of about 900 to 950 ° C. in a carburizing gas atmosphere in which propane gas or methane gas is modified.
 冷却(焼き入れ)工程(プロセスP3)では、蒸気の加熱工程で浸炭されたワーク1の焼き入れが実施される。従来、浸炭後の焼き入れには、ガス冷却が広く実施されているが、この発明における熱処理方法では、ミスト冷却が実施される。前述したように、ミスト冷却は、ガス冷却と比較して冷却効果が高い反面、多種多様なワーク全てに対応させて適切な冷却条件を設定するためには、冷却設備を調整することが困難であった。そこで、この発明では、ミスト冷却が行われる熱処理の前に、上記のように表面加工工程を設けている。表面加工工程でワーク1各部の表面粗さを調整することにより、その後のミスト冷却の際のワーク1各部の冷却速度を制御して、ミスト冷却によりワーク1の全体を均一に冷却することができるようにしている。 In the cooling (quenching) step (process P3), the workpiece 1 carburized in the steam heating step is quenched. Conventionally, gas cooling is widely performed for quenching after carburizing, but in the heat treatment method according to the present invention, mist cooling is performed. As described above, mist cooling has a higher cooling effect than gas cooling, but it is difficult to adjust cooling equipment in order to set appropriate cooling conditions for all kinds of workpieces. there were. Therefore, in the present invention, the surface processing step is provided as described above before the heat treatment in which the mist cooling is performed. By adjusting the surface roughness of each part of the work 1 in the surface processing step, the cooling rate of each part of the work 1 at the time of subsequent mist cooling can be controlled, and the whole work 1 can be uniformly cooled by mist cooling. I am doing so.
 上記のように、この発明における熱処理方法では、冷却設備側で調整を行うことなく、ワーク1自体の表面粗さを調整することにより、冷却工程におけるワーク1各部の冷却速度を制御することができる。したがって、従来の方法では、前述の図10に示したように、ワークの冷却速度を制御するために冷却設備側の調整が必要であったのに対して、この発明における熱処理方法では、冷却設備の噴射ノズルは、例えば図3に示すように、単純な配置のままでよい。また、冷却水の噴射量や噴射圧力なども一定に設定したままでよい。 As described above, in the heat treatment method according to the present invention, the cooling rate of each part of the work 1 in the cooling process can be controlled by adjusting the surface roughness of the work 1 itself without adjusting on the cooling equipment side. . Therefore, in the conventional method, as shown in FIG. 10 described above, adjustment on the cooling equipment side is necessary to control the cooling rate of the workpiece, whereas in the heat treatment method according to the present invention, the cooling equipment is used. The injection nozzles may remain in a simple arrangement as shown in FIG. 3, for example. Further, the injection amount and the injection pressure of the cooling water may be set to be constant.
 上記のように、ワーク1の表面粗さを調整することにより、冷却速度を制御してミスト冷却した場合のワーク1各部の冷却時間の測定結果を図4に示してある。また、比較のために、冷却速度を制御せずにミスト冷却した場合のワーク1各部の冷却時間の測定結果を図5に示してある。図5に示すように、ワーク1の表面粗さを調整することなく、冷却速度を制御せずにミスト冷却した場合は、温度測定点a(固定シーブ部2の外周端部分)および温度測定点b(固定シーブ部2の中間部分)で比較的に冷却速度が速いのに対して、温度測定点c(固定シーブ部2の内周端部分)では冷却速度が遅くなっている。したがって、この場合は、ミスト冷却の際のワーク1各部の冷却速度が大きくばらついていることが分かる。 FIG. 4 shows the measurement results of the cooling time of each part of the work 1 when the mist cooling is performed by adjusting the surface roughness of the work 1 as described above to control the cooling rate. For comparison, FIG. 5 shows the measurement results of the cooling time of each part of the work 1 when mist cooling is performed without controlling the cooling rate. As shown in FIG. 5, when the mist cooling is performed without adjusting the surface roughness of the workpiece 1 and without controlling the cooling rate, the temperature measurement point a (the outer peripheral end portion of the fixed sheave portion 2) and the temperature measurement point The cooling rate is relatively fast at b (intermediate portion of the fixed sheave portion 2), whereas the cooling rate is slow at the temperature measurement point c (inner peripheral end portion of the fixed sheave portion 2). Therefore, in this case, it can be seen that the cooling rate of each part of the work 1 during mist cooling varies greatly.
 これに対して、図4に示すように、この発明の熱処理方法により、ワーク1の表面粗さを調整し、冷却速度を制御してミスト冷却した場合には、温度測定点a、温度測定点b、および温度測定点c(固定シーブ部2の内周端部分)の間に大きな差は見られない。すなわち、図6に示すように、ワーク1の表面粗さを調整することなく、冷却速度を制御せずにミスト冷却した場合の冷却速度のばらつきと比較して、ワーク1の表面粗さを調整し、冷却速度を制御してミスト冷却を実施することにより、冷却速度のばらつきが大幅に低減していることが分かる。 On the other hand, as shown in FIG. 4, when the surface roughness of the workpiece 1 is adjusted by the heat treatment method of the present invention and the cooling rate is controlled and mist cooling is performed, the temperature measurement point a, the temperature measurement point There is no significant difference between b and the temperature measurement point c (the inner peripheral end portion of the fixed sheave portion 2). That is, as shown in FIG. 6, the surface roughness of the workpiece 1 is adjusted without adjusting the surface roughness of the workpiece 1 and compared with the variation in the cooling rate when the mist cooling is performed without controlling the cooling rate. And it turns out that the dispersion | variation in a cooling rate is reducing significantly by controlling a cooling rate and implementing mist cooling.
 このように、この発明における熱処理方法では、ワーク1の表面粗さを調整してミスト冷却の際の冷却速度を制御することにより、ワーク1各部の間で冷却速度のばらつきが小さく、ワーク1の全体を均一に冷却することができる。そして、ミスト冷却の際に、すなわち熱処理における焼き入れの際に、ワーク1の全体を均一に冷却できることにより、図7に示すように、熱処理による歪みや変形の発生を大幅に抑制することができる。したがって、ワーク1を寸法精度良く製作することができる。 As described above, in the heat treatment method according to the present invention, by adjusting the surface roughness of the workpiece 1 to control the cooling rate at the time of mist cooling, the variation in the cooling rate among the parts of the workpiece 1 is small. The whole can be cooled uniformly. And since the whole workpiece | work 1 can be cooled uniformly at the time of mist cooling, ie, the quenching in heat processing, as shown in FIG. 7, generation | occurrence | production of the distortion and deformation | transformation by heat processing can be suppressed significantly. . Therefore, the workpiece 1 can be manufactured with high dimensional accuracy.
 仕上げ加工工程(プロセスP4)では、上記のように浸炭および焼き入れされた後のワーク1の仕上げ加工が実施される。例えば、前工程で発生したスケールの除去や、仕上げ寸法を確保するための機械加工が実施される。上記のように、この発明における熱処理方法では、熱処理におけるミスト冷却の際に、ワーク1の全体を均一に冷却して、熱処理による歪みや変形の少ないワーク1を製作するすることができる。そして、熱処理後のワーク1の変形が小さいことにより、この仕上げ加工工程における仕上げ加工を省くこともできる。もしくは、従来と比較して、仕上げ加工の際の加工取り代が少なくなり、その分、仕上げ加工に要するコストを低減することができる。 In the finishing process (process P4), the finishing process of the workpiece 1 after carburizing and quenching is performed as described above. For example, removal of the scale generated in the previous process and machining for ensuring the finished dimensions are performed. As described above, according to the heat treatment method of the present invention, the entire work 1 can be uniformly cooled during the mist cooling in the heat treatment, and the work 1 with less distortion and deformation due to the heat treatment can be manufactured. And since the deformation | transformation of the workpiece | work 1 after heat processing is small, the finishing process in this finishing process can also be skipped. Or the machining allowance at the time of finishing is reduced compared with the conventional case, and the cost required for finishing can be reduced accordingly.
 上記のように、この発明における熱処理方法を適用してワーク1を製造した場合のコスト低減の効果を図8に示してある。この図8に示すように、ガス冷却によって焼き入れを行った従来方法によるワーク1の製造コストに対して、この発明の熱処理方法を適用したミスト冷却によって焼き入れを行った場合には、ワーク1の製造コストを大きく低減することができる。 As described above, the effect of cost reduction when the workpiece 1 is manufactured by applying the heat treatment method of the present invention is shown in FIG. As shown in FIG. 8, when the quenching is performed by mist cooling to which the heat treatment method of the present invention is applied, the workpiece 1 is manufactured by the conventional method in which quenching is performed by gas cooling. The manufacturing cost can be greatly reduced.
 以上のように、この発明に係る金属製部材の熱処理方法および熱処理された金属製部材によれば、熱処理を施すワーク1の表面粗さを調整することにより、そのワーク1をミスト冷却する際の冷却速度を制御することができる。すなわち、熱処理のためにワーク1を加熱した場合の熱量分布の熱量が大きい箇所は、熱処理の前工程で表面粗さが小さくなるようにワーク1の表面を加工しておくことにより、ミスト冷却の際の冷却速度を速くすることができる。反対に、熱量分布の熱量が小さい箇所は、熱処理の前工程で表面粗さが大きくなるようにワーク1の表面を加工しておくことにより、ミスト冷却の際の冷却速度を遅くすることができる。そのため、ミスト冷却のためのノズルの位置や数量あるいは冷却水の噴射状態など冷却設備側で調整することなく、ワーク1の冷却速度を制御することができる。その結果、ワーク1の大きさや形状等を変更した場合であっても、冷却設備の調整や変更を行うことなく、容易に、ミスト冷却によって均一でかつ適切な冷却を行うことができる。そして、ミスト冷却によってワーク1の全体が均一に冷却され、適切な熱処理が実施されることにより、熱処理による歪みや変形が少ないワーク1を製造することができる。その結果、熱処理後の仕上げ加工を省略もしくは簡略化することができ、ワーク1すなわちこの発明における金属製部材の製造コストを大幅に削減することができる。 As described above, according to the heat treatment method for a metal member and the heat treated metal member according to the present invention, by adjusting the surface roughness of the work 1 to be heat-treated, the work 1 is subjected to mist cooling. The cooling rate can be controlled. That is, in the portion where the heat quantity of the heat distribution when the work 1 is heated for the heat treatment is large, the surface of the work 1 is processed so that the surface roughness becomes small in the previous process of the heat treatment. The cooling rate can be increased. On the other hand, in the portion where the heat quantity of the heat distribution is small, the cooling rate at the time of mist cooling can be slowed by processing the surface of the workpiece 1 so that the surface roughness is increased in the previous process of heat treatment. . Therefore, the cooling rate of the workpiece 1 can be controlled without adjusting on the cooling facility side such as the position and quantity of nozzles for mist cooling or the injection state of cooling water. As a result, even when the size or shape of the workpiece 1 is changed, uniform and appropriate cooling can be easily performed by mist cooling without adjusting or changing the cooling equipment. And the whole workpiece | work 1 is cooled uniformly by mist cooling, and the workpiece | work 1 with few distortion and deformation | transformation by heat processing can be manufactured by implementing appropriate heat processing. As a result, the finishing process after the heat treatment can be omitted or simplified, and the manufacturing cost of the workpiece 1, that is, the metal member in the present invention can be greatly reduced.

Claims (11)

  1.  所定の加熱条件の下で金属製のワークを加熱する加熱工程と、前記加熱工程の後に、冷却水を噴霧して冷却を行うミスト冷却によって所定の冷却条件の下で前記ワークを冷却する冷却工程とを有する金属製部材の熱処理方法において、
     前記加熱工程の前に、前記加熱工程で加熱される際の前記ワークの熱量分布に応じて前記ワークの表面粗さを調整して加工する表面加工工程を有していることを特徴とする金属製部材の熱処理方法。
    A heating step for heating a metal workpiece under a predetermined heating condition, and a cooling step for cooling the workpiece under a predetermined cooling condition by mist cooling in which cooling is performed by spraying cooling water after the heating step. In a heat treatment method of a metal member having
    Before the heating step, a metal having a surface processing step of adjusting and processing the surface roughness of the workpiece according to the heat distribution of the workpiece when heated in the heating step A method for heat treatment of a manufactured member.
  2.  前記表面加工工程は、前記熱量分布の熱量が大きい箇所ほど前記表面粗さが小さくなるように前記ワークを加工する工程を含むことを特徴とする請求項1に記載の金属製部材の熱処理方法。 2. The method for heat-treating a metal member according to claim 1, wherein the surface processing step includes a step of processing the workpiece so that the surface roughness becomes smaller as the heat amount of the heat distribution increases.
  3.  前記冷却工程は、前記ミスト冷却における噴霧液滴の平均粒径が0.1mmから2.0mmの範囲内となるように前記冷却水を噴霧させる工程を含むことを特徴とする請求項1または2に記載の金属製部材の熱処理方法。 The cooling step includes a step of spraying the cooling water so that an average particle diameter of spray droplets in the mist cooling is in a range of 0.1 mm to 2.0 mm. The heat processing method of the metal members as described in any one of.
  4.  前記ワークは、鋼製の自動車部品を含むことを特徴とする請求項1から3のいずれかに記載の金属製部材の熱処理方法。 The heat treatment method for a metal member according to any one of claims 1 to 3, wherein the workpiece includes a steel automobile part.
  5.  前記ワークは、ベルト式無段変速機のプーリを構成する鋼製部材を含むことを特徴とする請求項4に記載の金属製部材の熱処理方法。 5. The heat treatment method for a metal member according to claim 4, wherein the workpiece includes a steel member constituting a pulley of a belt type continuously variable transmission.
  6.  前記表面加工工程は、機械加工によって前記ワークを加工する工程を含むことを特徴とする請求項1から5のいずれかに記載の金属製部材の熱処理方法。 The heat treatment method for a metal member according to any one of claims 1 to 5, wherein the surface processing step includes a step of processing the workpiece by machining.
  7.  前記表面加工工程は、ショットピーニング加工、ショットブラスト加工、サンドブラスト加工、研削加工、または研磨加工の少なくともいずれかによって前記ワークを加工する工程を含むことを特徴とする請求項1から5のいずれかに記載の金属製部材の熱処理方法。 6. The surface processing step includes a step of processing the workpiece by at least one of shot peening processing, shot blast processing, sand blast processing, grinding processing, or polishing processing. The heat processing method of the metal member of description.
  8.  所定の加熱条件の下で加熱した後に、冷却水を噴霧して冷却を行うミスト冷却によって所定の冷却条件の下で冷却する熱処理が施された金属製部材において、
     前記加熱条件の下で加熱される際の熱量分布に応じて表面粗さが調整されて加工されているとともに、その加工後に前記熱処理が施されていることを特徴とする熱処理された金属製部材。
    In a metal member that has been subjected to a heat treatment that is cooled under a predetermined cooling condition by mist cooling that is performed by spraying cooling water after being heated under a predetermined heating condition.
    A heat-treated metal member characterized in that the surface roughness is adjusted according to the heat quantity distribution when heated under the heating conditions, and the heat treatment is performed after the processing. .
  9.  前記金属製部材は、前記熱量分布の熱量が大きい箇所ほど前記表面粗さが小さくなるように表面加工されていることを特徴とする請求項8に記載の熱処理された金属製部材。 9. The heat-treated metal member according to claim 8, wherein the metal member is surface-treated so that the surface roughness becomes smaller as the heat amount of the heat distribution increases.
  10.  前記金属製部材は、鋼製の自動車部品を含むことを特徴とする請求項8または9に記載の熱処理された金属製部材。 10. The heat-treated metal member according to claim 8 or 9, wherein the metal member includes a steel automobile part.
  11.  前記金属製部材は、ベルト式無段変速機のプーリを構成する鋼製部材を含むことを特徴とする請求項10に記載の熱処理された金属製部材。 The heat-treated metal member according to claim 10, wherein the metal member includes a steel member constituting a pulley of a belt type continuously variable transmission.
PCT/JP2013/051570 2013-01-25 2013-01-25 Heat treatment method for metal member and heat-treated metal member WO2014115296A1 (en)

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